The present invention is directed to new detergent-dispersant compositions of high alkalinity for use as additives in lubricating oils and to the preparation of such compositions.
British Pat. No. 1,015,769 discloses the preparation of detergent-dispersants of high alkalinity having a base of alkylphenates and alkylbenzenesulfonates of alkaline-earth metals by sulfurization of a mixture containing an alkylphenol, an alkaline-earth metal alkylbenzenesulfonate, a C.sub.8 -C.sub.18 monoalcohol, an alkaline-earth base and glycol, precarbonation of the sulfurized mixture, alkalinization of the precarbonated mixture by an alkaline-earth base, carbonation, and then elimination of the glycol and recovery of the detergent dispersant. This process has the drawback that it requires the use of a C.sub.8 -C.sub.18 monoalcohol, which must then be recycled in practically anhydrous form.
Furthermore, while such a prior art process is satisfactory for the preparation of detergent-dispersants containing a high proportion of alkylphenates, it cannot, however, be used for the preparation of detergent-dispersants containing a high proportion of alkylbenzenesulfonates. Moreover, that process is adapted to the preparation of mixtures of alkylphenates and alkylbenzenesulfonates of calcium, barium, or strontium; it cannot be used for the preparation of detergent dispersants containing magnesium.
The present invention provides a process which does not have the drawbacks of the prior art process and which makes it possible to prepare detergent-dispersants having a base of metallic alkylbenzenesulfonates and alkylphenates of a TBN (Total Basic Number--ASTM Standard D 2896) of more than about 200, containing at least about 2 percent magnesium and optionally at least about 0.5 percent calcium.
It is, therefore, an object of the present invention to provide novel detergent-dispersant compositions useful as additives for lubricating oils having a base of alkylbenzene sulfonates and metal alkylphenates.
It is also an object of the present invention to provide a novel process for the preparation of detergent-dispersant compositions for use in lubricating oils.
It is also an object of the present invention to provide lubricating oils containing the novel additives of the invention.
Other objects of the present invention will be apparent to those skilled in the art from the present description.